The scale lies. Measurements don't. Track inches lost and gained over time — because a number on a scale can't tell you your jeans fit better.
Weight fluctuates by 2-5 pounds daily based on water retention, digestion, hormones, and time of day. Measurements change more slowly but more meaningfully — a lost inch from your waist represents real body composition change that the scale might not show for weeks. Many people lose inches while their weight stays the same because they're building muscle while losing fat.
Once a month is enough for most people. Measuring too frequently creates anxiety without meaningful data — measurements don't change week to week in ways you can see. Pick the same day of the month, same time of day (morning is best), and use the same measuring tape. Consistency in your method matters more than frequency.